The meaning conveyed by the morpheme chron- in each of the words listed: chronology, chronicle. chronic and chronogram means, TIME. The word "chron-" comes from the Greek word "khronos" meaning time. Chronology means the arrangement of dates of events in order. Chronicle means a record of a series of events. Chronic means persistent and chronogram means time writing.
"Unsupported and exaggerated statements" would be something that best characterizes an unreliable narrator, but this is of course somewhat subjective.
You need to adress a theme so that the audience knows how trajec it is. If you do not express or show a theme, it would be less dramatic. A drama is all about showing expression, scene, theme, costumes, etc.
Hope this helps! :)
